“A review of ISIS social media messaging during the week ending August 26 shows that militants are expressing an increased interest in the notion that they could clandestinely infiltrate the southwest border of US, for terror attack,” warns the Texas Department of Public Safety "situational awareness" bulletin, obtained by FoxNews.com.

It notes no known credible homeland threats or specific homeland attack plot has been identified. That assertion was underscored by Department of Homeland Security Secretary Jeh Johnson, who said Friday that DHS and the FBI are "unaware of any specific, credible threat to the U.S. homeland" from Islamic State.

The bulletin details numerous “calls for border infiltration” on social media, including one from a militant confirmed to be in Mosul, Iraq who explicitly beckons the “Islamic State to send a special force to America across the border with Mexico.”

This follows numerous posts on social media accounts of purported ISIS activity in the United States.

The tweet above was presumably blasted out by an ideological adherent of ISIS living in the U.S.: the photo on the left is the Old Republic Building in the Windy City, the one on the right is clearly the White House. So this begs the question: Is this tweet merely propagandist fodder, meant to deal a psychological blow to the American public and thwart U.S. intelligence officials, or should Americans be genuinely concerned?

This new DPS report from Texas indicates that yes, we should be concerned. The insecure nature of the U.S. southern border should always concern terror analysts, and with the rise of a new transnational well-funded terrorist power, its security becomes even more important.